Photocatalytic degradation of cationic dye in aqueous solution by TiO2 nanoparticle immobilized on termite hill soil

This work presented the preparation and characterization of TiO2/termite hill soil (TiO2-THS) and its photocatalytic application for cationic dye (methylene blue, MB) degradation in an aqueous solution. The TiO2-THS was prepared using the impregnation method. The material properties were characterized using techniques such as gas sorption, SEM, FTIR, XRF and XRD. Optimization of photocatalytic degradation of MB under visible light irradiation was carried out using Taguchi design approach. The effects of parameters affecting the photocatalytic degradation process, pH, initial concentration, irradiation time and photocatalyst loading, were examined. It was identified that the optimum values of the concentration, pH, time and photocatalyst loading were 50 mg/L, 6.0, 90 min and 0.5 g/L, respectively. At these optimum conditions, the predicted and experimental decolorization efficiencies were 96.31% and 95.76%, respectively. MB dye was almost completely mineralized after 90 min of visible light irradiation in the presence of the TiO2-THS catalyst. The prepared photocatalyst exhibited better stability and maintained its initial activity after being reused for six successive runs with a decolorization efficiency of 86.62%.